Microsoft Outlook Outage Disrupts Thousands
Microsoft Outlook outage on Nov. 12, 2026 hit Microsoft 365; Microsoft blamed unavailable servers and paused deployments, raising investor concern.
KEY TAKEAWAYS
- Microsoft said unexpectedly unavailable servers, not increased traffic, strained infrastructure and forced paused deployments and traffic redistribution.
- User-report aggregates peaked at more than 97,000 Outlook and about 38,000 Microsoft 365 reports.
- Microsoft restarted affected servers and tested a configuration change while mitigation remained ongoing.
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A Microsoft Outlook outage on November 12, 2026, disrupted Outlook, Teams, and Microsoft 365 services across the Americas. Microsoft said unexpectedly unavailable servers strained its infrastructure, prompting paused deployments, traffic redistribution, and server restarts.
Microsoft Account and Incident Response
Microsoft identified connectivity problems affecting Exchange Online, Teams, SharePoint Online, Microsoft 365 Copilot, and Microsoft Defender XDR in a Q&A post tracking incident MO1550821. The company said the elevated load was not caused by increased traffic but by a number of servers being unexpectedly unavailable, which strained the remaining infrastructure. To mitigate the issue, Microsoft paused deployments, redistributed connection traffic across its global infrastructure, tested a configuration change, and restarted affected servers.
Outage Scale, Timing, and Impact
At 2:07 p.m. ET, user-report aggregates showed more than 97,000 Outlook incidents, over 38,000 Microsoft 365 reports, and about 4,500 Teams reports. These figures reflect user reports and do not establish the number of affected customers.
Microsoft initially reported Exchange Online mailbox access problems in the Americas. A separate Teams disruption in North America occurred from about 9:45 to 10:53 a.m. ET, causing delays or failures in sending messages, updating conversations, and retrieving chat messages. Microsoft attributed this to resource contention and said Teams service health was restored.
The outage also disrupted Microsoft 365 connectors used by third-party AI tools. OpenAI warned that new Microsoft connector connections could fail and that tools might not function as expected. Anthropic traced its Microsoft 365 connector issues to an upstream provider.
Microsoft began investigating mailbox-access problems around 1:00 p.m. ET and warned at 1:07 p.m. that Microsoft 365 connectivity could be affected in any region. By 1:48 p.m., the company started redistributing connection traffic globally. At 2:31 p.m., Microsoft said it was restarting affected systems, pausing deployments, and testing configuration changes. As of 5:00 p.m. ET, mitigation efforts were ongoing without a definitive all-clear.
Microsoft did not disclose estimates of affected paying customers, revenue impact, service credits, financial guidance, or regulatory filings. The incident was described as a service degradation and connectivity event, not a security incident.
